This is a lower power picture of a bronchiole. Notice the lack of
cartilage pieces in the adventitia. If they were present, you will be
able to see them even at this magnification. The muscularis mucosae can
be easily made out. Part of the mucosa is thrown into little folds.
Look at these "lumps" carefully. Check the thickness of the wall of
this conducting passage associated with these folds and you know that
you are not dealing with a respiratory bronchiole (although at first
glance there may be some resemblance). PK1580. S1. Original mag. 25x.
H&E. Bronchiole. Lung. Respiratory System.